While a number of mat cutting and related devices are known, most require some amount of calculation in order to provide for the equal borders generally desired in such picture framing mats. While the calculations generally involved require no more than basic arithmetic, it is nevertheless extremely easy to make some small error and thus destroy a sheet of mat material by mismeasurement and cutting. While the use of a measuring rule containing two scales (half and full) removes some of the inconvenience from such mat cutting operations, the measurements must still be accomplished using a separate article of equipment which adds to the complexity of the operation to some extent.
Other mat cutting devices further require that the pencil or marker used to mark the cutting line on the mat material be operated manually along a straightedge. The cutting blade must then be aligned with the pencil mark and drawn along the line for the cut. This provides numerous possibilities for error in: (1) making the initial calculation, (2) marking the line for the cut, and (3) making the cut itself.
Another problem with other mat cutting devices is that generally the blade is applied to the mat board with relatively pressure provided with the fingers or a thumb. While mat cutting devices are known which provide retractable blades, the springs which apply the retraction pressure are generally relatively weak in order that the operator may easily override the spring pressure to make the cut. Such weak spring pressure may not cause the blade to retract when the cut is completed, due to the friction of the sides of the cut mat material on the sides of the blade.
The need arises for a mat cutting device which eliminates many of the above additional steps and calculations, but mechanically simplified over other such machines capable of performing such functions. The apparatus should combine as many of the various steps involved as possible. Moreover, the apparatus should be capable of being used over any suitable planar surface, rather than being integral with or requiring a specialized cutting or layout table or surface.